How do we select a site to install sensors
Criteria:
Experiences saltwater intrusion (near coast)
Blackwater system (manually subset coastal systems)
Experiences a seasonal change in color (green/[blue + red])
Accessible (bridges to install sensors or could use a boat)
Initial Analysis Methods
Manually selected rivers in NC
Selected rivers that I thought would be large enough and have high DOC contractions
Calculated distance from river mouth
Pulled landsat data
Using the Color of Rivers code, pulled landsat pixels that intersected NHD flowlines
Used the Dynamic Surface Water Extent (DSWE) algorithm, which casts pixels as not water (0), water high confidence (1), water low confidence (2), vegetated water high confidence (3), vegetated water low confidence (4) to remove non-water pixels.
Removed pixels with a DSWE of 0 and filtered for pixels with a mean DSWE less than 1.8. Chose this value from visual inspection on the intracoastal waterways.
Mean DSWE after 0s were removed for whole time series
Calculated spectral indices
Takeaways
I am not sure what remote sensing information to consider for this analysis. The Green/(Blue+Red) was correlated with salinity and DOC in the St. Johns but this is also the visual spectrum and influenced by a lot of factors. But using the Green/(Blue+Red) index, it seems there is seasonal variation in many coastal systems in NC.
Many rivers see an expected seasonal changes in the Green/(Blue+Red) index and higher values downstream (Perquimans, Pasquotank, and New). But some rivers show higher Green/(Blue+Red) values at the most upstream location (Scuppernong). This probably indicates cDOM is not solely driving the color of these waters. Algae, emergent vegetation, turbidity, or other things may be driving the color.
Scuppernong River
Time series
Zoomin on 2018 & 2019
Look at anomaly between the most down stream locations
Milltail Creek
Time series
Zoomin on 2017 & 2018
Look at anomaly between the most down stream locations
New River
Time series
Zoomin on 2008 to 2010
Look at anomaly between the most down stream locations
Pasquotank River
Time series
Zoomin on 2007 to 2010
Look at anomaly between the most down stream locations
Perquimans River
Time series
Zoomin on 2007 & 2010
Look at anomaly between the most down stream locations
White Oak
Time series
Zoomin on 2007 to 2010
Look at anomaly between the most down stream locations
